Scavenging port for internal-combustion engines



Jan. 17, 1923. 1,656,762

H. R. SETZ SCAVENGING PORT FOR INTERNAL COMBUSTION ENGINES Filed Auz. 1924 ,firOR V Patented Jan. 17, 1928.

UNITED STATES HANS R. SETZ, OF HIGI-ILAND PARK, EENNSYLVANIA; BERTHA E. SETZ ADMINISTRA- IR/IX OF HANS R. SE'IZ, DECEASED.

Y scavnneme roar non INTERNAL-COMBUSTION nnernns.

Application filed August 16. 1924. Serial No. 732,430.

My invention relates to an improvement in internal combustion engines and more particularly to engines of the Diesel type.

In internal combustion engines of the Diesel type working on the two cycle principle, the matter of effectively scavenging the cylinders after the power stroke has always presented a serious problem and one which, though attacked from various angles, has not heretofore been wholly solved.

In well known forms of Diesel type on gines, the scavenging of the cylinders is most effectively accomplished by the introduction of air under pressure into the cylinder after the exhaust has been opened and the major portion of the gases of combus tion allowed to escape. In practice, the air is admitted to the cylinders through scavenging ports at one side of the cylinders and passes out of the cylinders through the exhaust located on the opposite side of the cylinders, theoretically sweeping out of the cylinders'all of the gases of combustion not initially exhausted on the exhaust.

The present practice in scavenging while substantially effective leaves much to be desired and in fact fails to wholly clean out of the cylinders all of the gases of combustion,

opening of the with the result that the/new charge is to a I certain extent contaminated by gases of com bustion and the efficiency of the engine reduced.

Now it is the object of my invention to provide a novel construction of scavenging! port, applicable to the Diesel type internal combustion engine. and whereby the scav-r engine" air will be guided on its entry into the cylinder in such a manner as to cause it to so travel in the cylinder as to insure the most complete scavenging through the exhaust.

Having now indicated. in a general way,

the nature, purpose and advantage of my invention, I will proceed to a detailed description thereof, with reference to the accompanying drawings in which I have illust rated a preferred embodiment, and in which the figure is a vertical section through an engine cylinder embodying my invention.

In the drawing, A indicates the working cylinder supported on a frame B, and C a E, the upper and lower walls of which are flared upwardly and downwardly respectively ad acent the interior of the cylinder A, and which provides a passage for air from an air receiver F to the interior of the The scavenging port is divided,

cylinder. into three passages a, Z) and c by means of guide vanes G and H, which conform respectively to the contour of the upper and lower walls of the port and terminate ata distance, preferably less than the width of the passages between the vanes and the walls of the port, from the cylinder bore.

I By virtue of the provision of the guide vanes G and H in the scavenging port. it will be noted that the" scavenging air from the receiver will pass through the scaveng inn port and toward the cylinder in three separate streams, each of the streams having a definite direction. Further, it is to be noted that since the pressure drop in the scavenging" port is comparatively small, each of the air streams attain'its maximum velocity at the narrowest section of the pasthe section a and enters the cylinder in a line parallel. to the contour of the upper wall of the port, or at an. acute angle to the axis of the cylinder toward the top thereof. The air streampassmg throua'h passage 2) attains its maximum velocity in the section 7% in which section its flow is in a line normal to the cylinder axis and wit-hf the piston 1n lower dead center position would tend to pass straight across the cylinder boreand into the exhaust. With the piston in any position above lower dead center and not closing the scavenging; port, for example, as

indicated by dotted line c, this stream would becaused to deviate in an upward -di-' rection by the wall of the piston.

; The air stream passing through passage 0 will attain its maximum velocity in the sec tion 0' in a direction of travel parallel to lower port walls form a divergent orifice in the plane where the air stream from passage 0 impinges upon the stream from passage 6 the direction at the stream from passage Z) is readily influenced by the stream from passage c, with the result that the united streams flow into the cylinder in a direction toward the top thereot more or less-parallel to the stream from passage to. The upward deflection of the stream from passages b and 0 will be increased in the higherpositionsol' the piston to such an extent that in the higher positions of the piston leaving the port open, the combined streamsirom passages l) and'o will cause the stream from passage a to be deflected and travel with a steeper inclination toward the cylinder top. It will now be clear that lay virtue of my invention a scavenging port structure is provided which will insure the delivery o'tgthe scavengingair to the cylinder in a direct on toward the top of the cylinder. thus insuring substantially complete circulation at the scavenging air throughout the cylinder with resultant increase in efficiency of the scavenging. It will he noted that though I have described an embodiment of? my invention in detail, I do not intend that my invention be limited to the embodiment described, since it is capable of variations without departing from the invention. Further, while the attached drawing .rettersto asingle acting eylindenthe application O'flllj invention is notunderstood to be restricted to single acting engines only, but can with equal facility be used also on double acting engines. i

Having now tullydcscribed myinvention, what- I claim and desireto protect by Letters Patent is: i y e 1. In an internal combustion engine having a workingcylinder, a scavenging port opening into the cylinder, and n'ieans whereby the scavenging air is divided :in the port into a plurality o'l divergent streams and is rccoi'i'ibined therein to flow therefrom 1n streams therein, said piston being adapted when the port is partially opened to. divert one of said streamsinto another and'canse all of the scavenging air to flow into the engine cylinder in a direction toward the top thereot,

3. In an internal combustion engine having a working cylinder and a piston therein, a

scavenging port opening into the cylinder, and a vane in said port terminating short of the cylinder bore, said vane being adapted to divide the scavenging air within said portinto streams, direct a stream of air downwardly to impinge on the piston and be diverted thereby upwardly to impinge on another stream of air within said port when said port is partially opened.

5. Inan internal combustion engine having a cylinder, 'a divergent scavenging port having divergent walls opening into said cylinder, vanes dividing said port into separate passages through which the scavenging air passes in individual streams, said pistons being adapted to cause one of said. streams oi? air to impinge upon another stream and iause all the scavenging air to flow into the cylinder in a. direction toward the top thereof when the port is partially opened.

(3. In an internal con'ibustion engine having a working cylinder and a piston therein, a.

scavenging port opening into the cylinder at points above and below the lower dead center position of the piston, guide vanes within the port and terminating short ot the inner end thereof whereby the scavenging air is divided into a plurality of streams,

said guide vanes being so positionedvas to cause one of said streams to travel upwardly and one of said streams to travel downwardlymrd to impinge onthepiston trunk and diverted thereby to impinge on the:

other streams withinthe port and cause all the scavenging air totravel toward the top of the cylinder on is entry therein.

'7. .lnan internal combustion engine having a working cylinder, a scavenging port opening into theeylinder, and 'ineanswherehy the scavenging airis divided within the port-into a pluralit iwof streams and is recombined therein at a point adjacentthe cylinder hereto flow therefrom in a direc= tion toward the top of the cylinder when the port is open.

8. In an internal combustion engine having a working cylinder, a scavenging pert opening into the cylinder and means extending within the port and terminating short of the cylinder bore whereby the scavenging air divided into streams within the port and permitted to recombine therein at-a point adjacent the cylinder bore and before its entry into the cylinder. i

9. i In an internal combustion engine having a worlnrg cylinder and a plston therein, a

scavenging port opening into the cylinder stream at a point adjacent the cylinder bore and a vane extending within the port and and before the latter streams enter the cylterminating short of the cylinder bore inder. 10 whereby the scavenging air is divided into In testimony of which invention, I have streams within the port, one of which will hereunto set my hand at Chester, Penna., on

impinge on the piston and diverted thereby this 12th day of August, 1924. will be permitted to impinge on another HANS R. SETZ. 

